diff --git a/packages/@opticss/demo-app/package.json b/packages/@opticss/demo-app/package.json
index a1144700..3a51b7bc 100644
--- a/packages/@opticss/demo-app/package.json
+++ b/packages/@opticss/demo-app/package.json
@@ -51,7 +51,7 @@
   "devDependencies": {
     "@opticss/code-style": "^0.6.0",
     "@opticss/util": "^0.7.0",
-    "@types/mkdirp": "^0.5.1",
+    "@types/mkdirp": "^1.0.0",
     "@types/parse5": "^5.0.0",
     "@types/rimraf": "^2.0.2",
     "babel-cli": "^6.26.0",
diff --git a/yarn.lock b/yarn.lock
index c772a8fb..82543dc1 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -893,10 +893,10 @@
   resolved "https://registry.yarnpkg.com/@types/minimatch/-/minimatch-3.0.3.tgz#3dca0e3f33b200fc7d1139c0cd96c1268cadfd9d"
   integrity sha512-tHq6qdbT9U1IRSGf14CL0pUlULksvY9OZ+5eEgl1N7t+OA3tGvNpxJCzuKQlsNgCVwbAs670L1vcVQi8j9HjnA==
 
-"@types/mkdirp@^0.5.1":
-  version "0.5.2"
-  resolved "https://registry.yarnpkg.com/@types/mkdirp/-/mkdirp-0.5.2.tgz#503aacfe5cc2703d5484326b1b27efa67a339c1f"
-  integrity sha512-U5icWpv7YnZYGsN4/cmh3WD2onMY0aJIiTE6+51TwJCttdHvtCYmkBNOobHlXwrJRL0nkH9jH4kD+1FAdMN4Tg==
+"@types/mkdirp@^1.0.0":
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/@types/mkdirp/-/mkdirp-1.0.0.tgz#16ce0eabe4a9a3afe64557ad0ee6886ec3d32927"
+  integrity sha512-ONFY9//bCEr3DWKON3iDv/Q8LXnhaYYaNDeFSN0AtO5o4sLf9F0pstJKKKjQhXE0kJEeHs8eR6SAsROhhc2Csw==
   dependencies:
     "@types/node" "*"
 
@@ -7407,10 +7407,10 @@ preserve@^0.2.0:
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
   integrity sha1-gV7R9uvGWSb4ZbMQwHE7yzMVzks=
 
-prettier@1.17.0:
-  version "1.17.0"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.17.0.tgz#53b303676eed22cc14a9f0cec09b477b3026c008"
-  integrity sha512-sXe5lSt2WQlCbydGETgfm1YBShgOX4HxQkFPvbxkcwgDvGDeqVau8h+12+lmSVlP3rHPz0oavfddSZg/q+Szjw==
+prettier@1.17.1:
+  version "1.17.1"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.17.1.tgz#ed64b4e93e370cb8a25b9ef7fef3e4fd1c0995db"
+  integrity sha512-TzGRNvuUSmPgwivDqkZ9tM/qTGW9hqDKWOE9YHiyQdixlKbv7kvEqsmDPrcHJTKwthU774TQwZXVtaQ/mMsvjg==
 
 pretty-bytes@^5.0.0:
   version "5.3.0"